This invention relates to a valve timing control system for an internal combustion engine which is arranged to vary opening and closing timings of an intake valve and an exhaust valve in accordance with a driving state of the engine, and a lock release mechanism of the valve timing control apparatus for the internal combustion engine.
A Japanese Patent Application Publication No. 10-227236 discloses a valve timing control apparatus arranged to vary opening and closing timings of an intake valve to a most retard angle position or a most advance angle position by a lock mechanism arranged to be actuated through a hydraulic pressure and so on, in accordance with a circumference of a start of an internal combustion engine.